The University of Southampton

Author: Holly Wan

The Controversial Future of Inter-Species Chimeras

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Before the stem cells lecture, I was not aware of inter-species chimeras. During the lecture it was proposed that they could be the solution to organ shortages. I found this an interesting proposition, and imagined a world where no one dies waiting for an organ. However, the thought growing of organs in another animal made me uneasy, and since learning about it, I’ve been wondering whether I would accept one if I needed it.

So what are they?

An inter-species chimera is an organism containing cells from two or more genetically distinct species. After further research I found that pigs are the most promising candidates for this research due to similarities in organ size.

Process of their creation for organ transplantation:

Video: me

As I learned more, I gained an appreciation for the innovation of genetic engineering. In theory, inter-species chimeras could be used to provide unlimited transplantable organs, but at what cost?

Image: mouse-human chimeric embryo with human cells labelled with green fluorescent protein by Jian Feng [1]

How far can we really go?

Despite promise with recent experiments forming tissues, inter-species chimeras face massive challenges. The high risk of organ rejection reminded me how fragile biology is and how even innovations struggle to overcome nature.

There are also numerous ethical concerns. How does this technology challenge our perspectives on humanity and morality? I thought about how others would react to the process of their creation. Recognising the controversy of this topic, I surveyed the public to gauge their opinions.

“The most egregious abuses of medical research” – George W. Bush describing human–animal chimeras [2]

The results were evenly split, reflecting the diverse range of beliefs that should be considered.

Reasons ranged from fear of the unknown to ethical concerns. Many of those in favour argued saving lives justifies their use. Chimera creation involves genetic modification and experiments that could cause pain or distress to animals. Unlike human, animals cannot give consent. Is it ethical to use them for experiments solely for human benefit? Before their use, key concerns must be addressed first.

“The more you can show that it stands to produce something that will actually save lives … it shifts the scale of risk-benefit assessment in favour of pursuing research and away from those concerns that are more philosophical” – Vardit Ravitsky, a bioethicist [3]

To alleviate concerns, regulatory measures could be enhanced, implementing welfare assessments. Involving the public in decision-making would also help align advancements with societal values. However, even different countries have different opinions, and religious and cultural perspectives are also highly diverse.

It is clear that this topic needs to be approached sensitively, considering both individual beliefs and societal values.

What other choice do we have?

The demand for organ transplants is not decreasing. So, what are our other options? One possible solution is in-vitro stem cells allowing for patient-specific organs. Integrating techniques such as 3D bio-printing could also help us move towards a brighter future. [4]

Image: 3D bio-printing used to synthesise tissues [5]

My final thoughts

I’m torn between saving lives and animal welfare. After more research, the complexity of the issues is only more apparent. The number of articles expressing concerns has greatly impacted my perspective, highlighting the key considerations needed before implementation.

I believe we should innovate, but within boundaries. Should we set clear limits on inter-species organ growth, and if so, what should those be? Whilst some have argued the potential to save lives outweighs concerns, I don’t think it is that clear cut. The question isn’t just whether we can create inter-species chimeras, but whether we should.

References:
[1] https://www.the-scientist.com/chimera-research-opens-new-doors-to-understanding-and-treating-disease-71254
[2] https://www.pnas.org/doi/10.1073/pnas.1615787113
[3] https://www.washingtonpost.com/news/speaking-of-science/wp/2017/01/26/scientists-create-a-part-human-part-pig-embryo-raising-the-possibility-of-interspecies-organ-transplants/
[4] https://www.sir.advancedleadership.harvard.edu/articles/engineering-high-tech-solutions-organ-shortage#:~:text=Joseph%20Vacanti%2C%20Professor%20of%20Surgery,an%20interdisciplinary%20field%20that%20applies
[5]https://blogs.manchester.ac.uk/mioir/2023/06/09/can-3d-bioprinting-cure-organ-trafficking/

Knee replacements: Cost for Mobility

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“We don’t appreciate what we have until it’s gone.” This phrase resonated deeply with me during the lecture on joint replacements. We often take for granted the ability to move and stand without pain—until one day, we can’t. Millions of lives have been transformed by the invention of knee replacement, restoring people’s movement but also their independence. But what are the challenges of these replacements and what does their future look like?

Evolution of knee replacements

The idea of replacing damaged joints isn’t new and has been around for hundreds of years where ancient civilisations experimented with rudimentary prosthetics. Modern knee replacement surgery, or total knee arthroplasty (TKA) however, only emerged in the mid-20th century. Advances in materials, surgical precision, and rehabilitation have meant that patients today can regain almost all lost function. Whilst these improvements have been greatly beneficial, there are still risks and limitations involved.

image: Fixed vs mobile bearing of knee replacements https://link.springer.com/chapter/10.1007/978-981-16-8591-0_3

More Than Just a Mechanical Problem?

Engineering is at the core of a knee replacement where surgeons remove damaged bone and replace it with metal and synthetic components that are specifically designed to mimic the joint’s natural function. The real challenge however, is in how the body allows the artificial joint to work within our bodies, where ligaments, tendons, and muscles must adjust to the artificial joint, and imbalances in force distribution can lead to complications such as implant loosening. The risk of rejection is also prevalent as the body may recognise the implant as foreign, triggering low-grade inflammation that can affect the implant’s longevity.

As with any surgery there is the emotional and psychological side. How does it feel having to relearn simple movements such as walking? Regaining autonomy can be life-changing, but rehabilitation can be long and demanding.

Challenges and Ethical Considerations

Despite its success and widespread use, it still has its limitations.

  • Longevity of implants: A knee prosthesis only lasts 15–20 years and so younger patients may require multiple complex surgeries.
  • Access to prosthetics: Not everyone can afford a knee replacement. Is it right that orthopaedic treatments are more readily available to those with financial means?
  • Surgical risks: Infections and rejection are still major risks.

In a recent BBC article from last year, Heather considered herself “lucky” to have had her left knee replaced after two years of pain. This article highlights a wider systemic issue in healthcare-availability. The question remains as how can we solve this?

This shows that there is still a long way to go when talking about this type of technology and highlights the need for continuous innovation in this area.

Future of Knee Replacements: Can We Do Any Better?

With recent advancements in areas such as 3D printing and robotic-assisted surgery, the future of knee replacements is still promising. One day, could we use cartilage grown in a lab to produce personalised implants? And could AI-driven rehabilitation programs increase patients’ recovery outcomes?

This lecture changed the way I think about joint replacements as a field that intersects engineering, biology, and ethics. It made me think about the the privilege of mobility and the importance of continuous innovation in medical technology.